Semiconductor chips and devices may include a variety of logic circuits and sub-systems each operating at different voltage levels. A system fabricated in a chip may be designed to communicate with external systems through communication ports where the logic fabricated in the chip may be operating at a different voltage level than the operating voltage level of the external systems coupled to the chip. Level shifter circuits are used to alter the voltage levels to bring the level of the signal operating in the first voltage domain to the level of the voltage of the second voltage domain.